LA CONNER (July 30, 2004) – The key to big salmon runs may lie in small sections of habitat, scientists at the Skagit River System Cooperative are finding.
According to the tribal consortium’s research, pocket estuaries are exceptionally important for the imperiled Skagit River chinook salmon.
“Our research is designed to reach one goal: the recovery of Skagit River chinook salmon,” said Lorraine Loomis, fisheries manager with the Swinomish Tribe. Skagit River chinook are listed as “threatened” under the federal Endangered Species Act. “This pocket estuary work has a lot of promise, and could help us toward that goal.”
SRSC is the natural resources arm of the Swinomish and Sauk-Suiattle tribes. For the past 10 years, scientists at SRSC (and its predecessor, the Skagit System Cooperative) have been studying every aspect of chinook salmon life history in the area. Learning how salmon fry migrate through the Skagit River delta, for example, has revealed that lost delta habitat and pocket estuaries are significantly limiting how many chinook the river can produce.
The tribal natural resources organization is now finding that, in the marine waters around the Skagit River delta, chinook congregate in pocket estuaries. A pocket estuary, like its larger counterpart, is a partially enclosed marine body of water where the salt water is diluted by freshwater. The difference is that pocket estuaries are much smaller – some in the Skagit basin are four acres or less. Chinook and other fish simply love pocket estuaries, using these sheltered habitats to feed, hide from predators, and prepare for their transition to the open ocean.
Because these areas are often low-bank waterfront property, though, people love pocket estuaries too – and love them to death in many cases. Of the 114 such sites that SRSC has identified, development has devastated about 80 percent.
“This work will help us figure out what kind of pocket estuaries salmon prefer to use, where productive pocket estuaries used to be, and where they could be in the future,” said Aundrea McBride, a research ecologist with SRSC. “That will reveal possible restoration opportunities in the future.”
The SRSC study, now in its second year, covers an area stretching from Deception Pass in the north to Possession Sound in the south. To cover this wide swath of nearshore habitat, SRSC has teamed up with the Tulalip, Stillaguamish and Samish tribes. The tribes are monitoring 11 productive pocket estuaries intensively throughout the year; approximately 30 other sites will also be tested, though not as regularly. For points of comparison, they are also monitoring three pocket estuaries that have been destroyed by development to see if fish are still trying to use those sites. They will continue sampling through June.
“By learning about salmon use patterns – what pocket estuaries they use and why – we can prioritize our restoration efforts better,” said McBride. “We hope this research will be a foundation for establishing habitat preservation priorities in other regions as well.”
Researchers stress that pocket estuaries, however important, are not the lone silver bullet for salmon recovery.
“Pocket estuaries are not a replacement for lost delta habitat; the total acres of pocket estuaries in Whidbey Basin are not even close to the acres of delta habitat that could be restored,” said McBride. “Pocket estuaries are an important part of the salmon recovery story, but are not a replacement for delta habitat.”
The combined project is funded by a $40,000 grant from the Northwest Straits Commission.
For more information, contact: Jeff Shaw, Northwest Indian Fisheries Commission, 360.424.8226; Lorraine Loomis, Swinomish Tribe, 360.466.3163; Aundrea McBride, Skagit River System Cooperative, 360.466.4691; Eric Beamer, Skagit River System Cooperative, 360.466.7241.